recursion square root

[game2d]

how to test if a num is a square root?
ex: 9 is square root
3 is not square root
/////////////////////////////////////////////

x = 0; //always start at 0
y = 101010;  //is this a square root?
square(x, y){
     if((x*x) >= y){       //not a square root
         return false;
     }
     else if((x*x) == y)    //it is a square root
         return true;
     }
     else{                 //inc x by 1
        square(x+1, y);
     }
}

this algorithm works fine when y is small int. ex 4, 10, 20.
but when i put y to be large ex 10000. than i get it to problem.
this is bc x start out with 0 and slowing get inc by 1. this takes alot of time.

is there better way to do this by using recursion? may be there is some formula that i dont know about.

[Luuk]

change the increment part.....

start with increments of i.e. 100
if x*x>y (not x*x>=y), than do :
x=x-100, and change increments to 10

or, if google, and find this

[game2d]

i am not sure how to do this part: x=x-100, and change increments to 10

x = 100; //always start at 0
y = 101010;  //is this a square root?
square(x, y){
     if((x*x) > y){       //not a square root
         return false;
     }
     else if((x*x) == y)    //it is a square root
         return true;
     }
     else{                 //inc x by 1
        square(x+1, y);
     }
}

[Nepomuk]

Well, there are a few things you could do. Personally, I'd have a look at the so called Babylonian method for computing square roots; it's quite simple and relatively easy to implement in a recursive manner. Also, it should be much faster than your current method.